When you think about things that go ‘bump’ in the night, it may not immediately come to mind but car bumpers are indeed applicable. Bumpers are those front and rear protective guards that protect our cars from crumpling like a sheet of crushed aluminum foil. Many modern bumpers are made from thermoplastic or thermoset plastic. The thermoset material is automotive urethane or PUR. It is a bi-material solid that forms in the mold as two liquid chemicals flow in and combine into a rigid solid. You cannot melt urethane with a plastic welder. The actual processes have more in common with brazing metals than melting and refusion like a welder.
Thermoset Plastic Car Bumper Repair
A V-groove is cut using a rotary tool about half the thickness and then the technician will roughen the edges with 80 grit sandpaper. Paint is also removed from around the area. The welder is kind of like an industrial sized glue gun that melts a rod of plastic. The airless plastic welder then fills the grove using a special polyurethane rod. The heat setting should produce a completely melted and clear material to fill the groove without any discoloration or bubbling. The tip must be held above the surface. Care must be taken as too much heat will break the chemical bond and adversely affect the bumper material. Reheat and smooth the weld with the welding tip shoe. V-groove the back side and repeat. Grind the weld to a smooth contour the apply the appropriate filler. Torn out holes are repaired by tapering the plastic around the hole. Taping with aluminum body tape on one side, the hole is filled with polyurethane rods melted into the hole. It is then smoothed and the hole re-drilled.
It takes experience and a steady hand to repair the thermoset plastic bumpers plus all the right equipment. Not really a DIY job unless you want to invest more in tools than the repair will cost.
Thermoplastic Bumper Scratch & Dent Repair
Whereas thermoset plastics are repaired with a process like brazing, the repair of the thermoplastic bumpers is a true fusion process. These bumpers are set by melting pellets of plastic and filling a mold to set and cool. The plastic is TPO or TEO. TPO is thermoplastic olefin, while TEO is thermal elastic olefin, and these plastics are quickly becoming the primary material in the automotive industry inside and out, even under hood plastic components. These plastics melt and can be repaired by a fusion welding process. These are elastic materials and not a rigid material like the thermoset plastics. A V-groove is cut in the tear and paint is removed from the area. Sandpaper the groove and the groove edges. A rod is melted into the joint and the temperature is set to fuse the base material and filler rod. There is a special technique that the technician will use to ensure a proper fusion and mixing of the filler and base materials. The backside is grooved and welded. The repair is sanded using a heavy grit paper and the filler material is added and smoothed over. After the filler is added it is sanded, primer and then painted.
Auto Body Dent Removal & More in Dallas, Texas (Just Minutes Away from Addison, Balch Springs, Carrollton, Cedar Hill, Coppell, DeSoto, Duncanville, Farmers Branch, Ferris, Garland, Grand Prairie, Grapevine, Irving, Lancaster, Lewisville, Mesquite, Ovilla, Richardson, Rowlett, Sachse, Seagoville, Sunnyvale & Wylie, TX)
Experience, knowledge and training make for the best plastic repair technicians. Knowledge of the plethora of plastic repair products is needed to match the best material to the job at hand. Top Notch Auto Body & Mechanics are knowledgeable and experienced in auto body repair. Call us to discuss your next project today!
